package tinkoff.advent12;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class Solution {
    private static final int[] firstPrimes = {
            3, 5, 7, 11, 13, 17, 19, 23, 29,
            31, 37, 41, 43, 47, 53, 59, 61, 67, 71,
            73, 79, 83, 89, 97, 101, 103, 107, 109, 113,
            127, 131, 137, 139, 149, 151, 157, 163, 167, 173,
            179, 181, 191, 193, 197, 199, 211, 223, 227, 229,
            233, 239, 241, 251, 257, 263, 269, 271, 277, 281,
            283, 293, 307, 311, 313, 317, 331, 337, 347, 349,
            353, 359, 367, 373, 379, 383, 389, 397, 401, 409,
            419, 421, 431, 433, 439, 443, 449, 457, 461, 463,
            467, 479, 487, 491, 499, 503, 509, 521, 523, 541,
            547, 557, 563, 569, 571, 577, 587, 593, 599, 601,
            607, 613, 617, 619, 631, 641, 643, 647, 653, 659,
            661, 673, 677, 683, 691, 701, 709, 719, 727, 733,
            739, 743, 751, 757, 761, 769, 773, 787, 797, 809,
            811, 821, 823, 827, 829, 839, 853, 857, 859, 863,
            877, 881, 883, 887, 907, 911, 919, 929, 937, 941,
            947, 953, 967, 971, 977, 983, 991, 997, 1009, 1013,
            1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069,
            1087, 1091, 1093, 1097, 1103, 1109, 1117, 1123, 1129, 1151,
            1153, 1163, 1171, 1181, 1187, 1193, 1201, 1213, 1217, 1223,
            1229, 1231, 1237, 1249, 1259, 1277, 1279, 1283, 1289, 1291,
            1297, 1301, 1303, 1307, 1319, 1321, 1327, 1361, 1367, 1373,
            1381, 1399, 1409, 1423, 1427, 1429, 1433, 1439, 1447, 1451,
            1453, 1459, 1471, 1481, 1483, 1487, 1489, 1493, 1499, 1511,
            1523, 1531, 1543, 1549, 1553, 1559, 1567, 1571, 1579, 1583,
            1597, 1601, 1607, 1609, 1613, 1619, 1621, 1627, 1637, 1657,
            1663, 1667, 1669, 1693, 1697, 1699, 1709, 1721, 1723, 1733,
            1741, 1747, 1753, 1759, 1777, 1783, 1787, 1789, 1801, 1811,
            1823, 1831, 1847, 1861, 1867, 1871, 1873, 1877, 1879, 1889,
            1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987,
            1993, 1997, 1999, 2003, 2011, 2017, 2027, 2029, 2039, 2053,
            2063, 2069, 2081, 2083, 2087, 2089, 2099, 2111, 2113, 2129,
            2131, 2137, 2141, 2143, 2153, 2161, 2179, 2203, 2207, 2213,
            2221, 2237, 2239, 2243, 2251, 2267, 2269, 2273, 2281, 2287,
            2293, 2297, 2309, 2311, 2333, 2339, 2341, 2347, 2351, 2357,
            2371, 2377, 2381, 2383, 2389, 2393, 2399, 2411, 2417, 2423,
            2437, 2441, 2447, 2459, 2467, 2473, 2477, 2503, 2521, 2531,
            2539, 2543, 2549, 2551, 2557, 2579, 2591, 2593, 2609, 2617,
            2621, 2633, 2647, 2657, 2659, 2663, 2671, 2677, 2683, 2687,
            2689, 2693, 2699, 2707, 2711, 2713, 2719, 2729, 2731, 2741,
            2749, 2753, 2767, 2777, 2789, 2791, 2797, 2801, 2803, 2819,
            2833, 2837, 2843, 2851, 2857, 2861, 2879, 2887, 2897, 2903,
            2909, 2917, 2927, 2939, 2953, 2957, 2963, 2969, 2971, 2999,
            3001, 3011, 3019, 3023, 3037, 3041, 3049, 3061, 3067, 3079,
            3083, 3089, 3109, 3119, 3121, 3137
    };

    public static void main(String[] args) throws IOException {
        List<Integer> primes = new ArrayList<>();
        for (int n = 9_999_001; n < 10_000_050; n += 2) {
            boolean ok = true;
            for (int firstPrime : firstPrimes) {
                ok = n % firstPrime != 0;
                if (!ok || firstPrime * firstPrime >= n) break;
            }
            if (ok) primes.add(n);
        }


        long ans = 0, maxP1 = 0, maxP2 = 0;
        for (long p1 : primes) {
            for (long p2 : primes) {
                if (p1 > p2) continue;
                if (p2 - p1 > 100) break;
                long tmp = p1 * p2;
                if (tmp < 100_000_000_000_000L && tmp > ans) {
                    ans = tmp;
                    maxP1 = p1;
                    maxP2 = p2;
                }
            }
        }
        System.out.println(maxP1 + " * " + maxP2 + " = " + ans);

    }
}
